How can I have permission for read and write? Using High Sierra on a 2009 iMac.

I want to be able to drag items into my volume without having to type in my password every time. Here is what happens if I try to revise permissions: The operation can’t be completed because you don’t have the necessary permission.

There also is this when running disk utility:

warning: Overallocation Detected on Main device: (12047260+1) bitmap address (10b1d86)

warning: Overallocation Detected on Main device: (15160205+1) bitmap address (10b1467)

warning: Overallocation Detected on Main device: (18382974+1) bitmap address (10b0de3)